What’s Your Sex Number?

1 Day a Week for Your Weight

Sex prompts your brain to release oxytocin, which can improve your sleep, says Helen Fisher, Ph.D., biological anthropologist at Rutgers University in New Brunswick, New Jersey. And more zzz's could mean fewer pounds. Sleep regulates hunger-related hormones ghrelin and leptin, helping you say no to seconds.

Stephanie Rausser

2 Days a Week for Your Sniffles

Peeps who do it two or three times weekly have 30 percent more immunoglobulin A proteins, which protect against illness, in their system than others do, a study from Wilkes University notes. The researchers believe the relaxing, mood-lifting effects of sex may play a role in keeping you healthy.

Stephanie Rausser

3 Days a Week for Your Heart

It's more fun to hop on a guy than an elliptical, but both aid your ticker. Sex revs heart rate and blood flow. People who do it three times a week could see their risk for a fatal heart attack cut in half, a study from the University of Bristol shows.

Peter Dazley/Photographer's Choice

4 Days a Week for Your Skin

Couples who do it routinely look four to seven years younger (per study subjects asked to guess couples' ages) than those who have less sex, scientists at the Royal Edinburgh Hospital in Scotland report. Could be because sex produces human growth hormone, which may lower body fat and smooth complexion, the study authors say.

David Gubert

5 Days a Week for Your Outlook

Frequent sex is linked with increased optimism, energy, focus and creativity. So even when you're not rolling around in the sack, you could feel more positive and have a happier relationship. Plus, all that focus and motivation could help you perform better at work, Fisher says.

Stephanie Rausser

6 Days a Week for Your Brain

To be a smarty pants, you gotta drop your pants ... as many times as possible. High-five if you get to six, but even one booty sesh is good for your smarts. When you have sex, it increases blood flow to the brain, releasing hormones that may enhance your intellectual capacity, according to Barb DePree, M.D., an ob/gyn in Holland, Michigan. And get this: It might even create new brain cells!

John Dolan

7 Days a Week for Your Mood

We're impressed if you're doing it every day. Wow. Even if you're not, though, getting down can help you de-stress. "Regular sex can reduce anxiety," possibly because of the endorphins it produces, says Jonathan R. Cole, M.D., an internist in Westlake Village, California.